I think that attraction has a lot to do with what you are used to or comfortable with. Beauty and attraction are relative. For instance, I have many friends who are coupled with people who share similar physical features.
Case in point: Two friends of mine who are married; she is 5'10, he is 6'2. They both have long torsos, long legs, are athletic and lean. Both have larger noses, close-set eyes, and large and beautiful smiles. It seems to me that they find comfort in looking at a face that is slightly familiar to their own. Alternatively, if you look at their differences, she has dark hair, skin and eyes and he has light hair, skin and eyes, they may be different enough to still be attractive to each other.
There are definitely cases where matching someone physically isn't important, but I think there is something to be said with what fits and compliments our body type and comfort level.
Next time you're walking along the street, look at the couples and find their similarities. I'm always amazed.
And yes, I have to be physically attracted to someone and they have to be physically attracted to me. And the attraction has to be on a similar level or else it won't work, at least not for me. They have to be smart too.